Spinning unit and air jet spinning machine having such a spinning unit

ABSTRACT

An air jet spinning machine, air jet spinning machine for producing a thread from a fed sliver, and method for detecting a thread strength, which falls below a target value, of a thread produced at a spinning unit of an airjet spinning machine are provided. A thread manipulation unit is arranged in the region between the airjet spinning machine and the spooling device, which thread manipulation unit acts mechanically on the thread and exerts an adjustable thread tension influencing force, in particular an adjustable braking force, compression force and/or clamping force, onto the thread in order to variably increase thread tension. In the method, an adjustable thread tension influencing force is exerted onto the thread, and a thread breakage and/or thread breakage rate are/is detected and compared with a specified target rate, and thread breakage and/or deviations of thread breakage rate beyond a predetermined limit value are displayed and/or evaluated.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a 35 U.S.C. 371 national stage filing of International Application PCT/EP2020/083665, filed Nov. 27, 2020, which claims priority from EP National Patent Application No. 19212518.5, filed Nov. 29, 2019, entitled “Spinnstelle and Luftspinnmaschine umfassend eine solche Spinnstelle”, the entire contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention concerns a spinning unit as well as an air jet spinning machine having at least one spinning unit for manufacturing a thread from a supplied fibre band, comprising: an air-jet spinning device for forming a thread from a fibre band fed via a drafting system, and a winding device for taking up the thread on a take-up package. Furthermore, the present invention relates to a method for detecting a thread strength of a thread manufactured at a spinning unit of an air jet spinning machine which falls below a target value.

BACKGROUND OF THE INVENTION

Spinning units as well as air jet spinning machines having a plurality of spinning units arranged side by side are known from the prior art in a variety of embodiments. Apart from rotor and ring spinning machines, air jet spinning machines are the most frequently used machines for manufacturing a thread from a fibre material. In air spinning, a fibre band is typically drafted according to the yarn count to be achieved, by means of a drafting system, and is then fed to an air-jet spinning device. Inside the air-jet spinning device, the outer fibres of the sliver are wound around the inner core fibres of the fibre band by means of a vortex air flow generated by one or more spinning air nozzles and thus form the wrap fibres, which are decisive for the desired thread strength of the thread. The thread thus formed is finally taken up via a take-up duct of the air-jet spinning device and, for example, wound onto a tube.

Due to the process, it is possible that blockages, contamination or fluctuations in the air/spinning pressure of the air-jet spinning device, e.g. of the air spinning nozzle or an area immediately upstream thereof, occur from time to time during the spinning. The blockages or contamination result/results primarily from fibres of the sliver that accumulate upstream of the air spinning nozzle and cause the wrap fibres to no longer be wound around the core fibres in the specified manner. Because of the importance of the wrap fibres for the thread strength, this has the consequence that the thread exiting the air-jet spinning device no longer has the required thread strength. The defective thread has what are referred to as weak places, which cannot be reliably detected by known methods, e.g. optical methods.

SUMMARY OF THE INVENTION

Proceeding therefrom, the present invention addresses the problem of providing a spinning unit as well as an air jet spinning machine which makes it possible reliably to detect threads emerging from the air-jet spinning device with an inadequate thread strength. Furthermore, the present invention addresses the problem of providing a method for detecting a thread strength of a thread manufactured at a spinning unit of an air jet spinning machine which falls below a specified target value.

The present invention solves the problem by means of a spinning unit for an air jet spinning machine for manufacturing a thread from a supplied fibre band, comprising: an air-jet spinning device (5) for forming a thread (15) from at least one fibre band (14) fed via a drafting system (4), and a winding device for taking up the thread on a take-up package (9), characterised in that, in the area between the air-jet spinning device (5) and the winding device, a thread manipulation unit (17) is arranged, which acts mechanically on the thread (15) and exerts an adjustable thread-tension-influencing force, in particular an adjustable braking, compressive and/or clamping force, on the thread (15) to variably increase the thread tension.

The present invention solves the problem by means of an air jet spinning machine, characterised in that the thread manipulation unit (17) is arranged in the area between the air-jet spinning device (5) and a thread take-up unit (6 a, 6 b).

The present invention solves the problem by means of a method for detecting a thread strength of a thread manufactured at a spinning unit of an air jet spinning machine which falls below a target value, wherein an adjustable thread-tension-influencing force is applied to the thread (15) by means of a thread manipulation unit (17), which is arranged in the area between an air-jet spinning device (5) and a winding device and acts mechanically on the thread, and a thread break and/or thread break rate is detected and compared with a specified target rate, and the thread break and/or deviations of the thread break rate beyond a predefined limit value are indicated and/or evaluated.

Advantageous further developments of the spinning unit and the air jet spinning machine are stated in the dependent claims.

The spinning unit according to the present invention is characterised in that, in the area between the air-jet spinning device and the winding device, a thread manipulation unit is arranged, which acts mechanically on the thread and exerts an adjustable thread-tension-influencing force on the thread to variably increase the thread tension.

The thread manipulation unit of the spinning unit according to the present invention makes it possible to set the thread tension of the thread emerging from the air-jet spinning device to a defined value in a defined manner in the area between the air-jet spinning device and the winding device. The thread tension that can be set depends on the expected thread strength of the spun thread and can be selected in such a way, for example, that fluctuations in the thread strength within an acceptable tolerance range have no influence on the spinning process. However, if the thread strength falls below a maximum permissible limit value range, the higher thread tension produced by the thread manipulation unit results in a thread break, even one of which can be evaluated as an indication of malfunctions during the spinning process which are the cause of a reduced thread strength.

The thread manipulation unit acts on the thread in a mechanical manner and is designed in such a way that the thread tension can be variably adjusted, according to the thread to be spun, by means of an adjustable thread-tension-influencing force acting on the thread. The thread-tension-influencing force can preferably be implemented by means of an adjustable braking, compressive and/or clamping force.

By increasing the thread tension using the thread manipulation unit, threads with weak places can be reliably identified by means of provoked thread breaks, so that measures can be immediately taken at the spinning unit to eliminate the causes of the weak places. The manufacture and subsequent winding of threads with an inadequate thread strength at the spinning unit according to the present invention can thus be reliably prevented, since malfunctions can be detected and eliminated at an early stage.

The thread-tension-influencing force, which increases the thread tension, can in principle be adjusted in any way by means of the thread manipulation unit acting mechanically on the thread. However, according to an advantageous further development of the present invention, the thread manipulation unit has at least one adjustable clamping means toward the thread. With this clamping means, which preferably acts on the thread transversely to the thread running direction, the clamping force acting on the thread and thus the thread tension can be adjusted to a specified value in a simple and reliable manner. The clamping means can be designed in such a way as to rest on the thread at a point or—with respect to the direction of the thread path—over a section, thus producing a sufficiently high thread-tension-influencing force or clamping force.

In particular, planar contact of the clamping means, of which there is at least one, over a section of the thread makes it possible to adjust the clamping force on the basis of the length of contact with the clamping means in such a way that no damage to the thread due to the interaction with the clamping means is to be feared.

In addition to the advantageously provided use of at least one clamping means for increasing the thread tension, it is also possible to increase the thread tension alternatively or additionally by changing the thread path, in which case the thread manipulation unit has correspondingly suitable deflection means for this purpose, by means of which the thread path can be variably adjusted. The thread tension can thus be set particularly reliably in accordance with the deflection of the thread by the deflection means, the deflection means exerting a compressive force on the thread according to the position of the deflection means. The embodiment of the deflection means can in principle be freely selected; according to a particularly advantageous embodiment of the present invention, the thread manipulation unit has an adjustable eyelet for variably altering the thread path. According to this preferred embodiment of the present invention, the thread passes through the adjustable eyelet of the thread manipulation unit, and the positioning of the eyelet in engagement with the thread causes the thread path to be altered and a compressive force to be exerted on the thread. The compressive force is determined by the position of the eyelet relative to the position in which the thread path is not influenced by the thread manipulation unit. The adjustable eyelet thus ensures, in a particularly reliable way, an interaction of the thread manipulation unit with the thread. At the same time, the design of the eyelet, e.g. the surface finish, allows damage to the thread in interaction with the eyelet to be reliably avoided.

The design of the advantageously provided clamping means, of which there is at least one, can in principle also be freely selected, and therefore it is basically possible to provide a thread-protecting design for this clamping means as well. According to a particularly advantageous embodiment of the present invention, the clamping means is formed by a disc tensioner and/or gate tensioner. The use of such tensioners offers the advantage that they allow a particularly accurate adjustment of the clamping and thus the clamping force. When disc tensioners are used, for example, these can act on the thread by means of an adjustable spring stress, in which case a clamping force is reliably exerted on the thread over the length of contact of the discs with the thread and at the same time damage to the thread is avoided in a particularly reliable manner due to the length of contact.

Furthermore, according to a preferred embodiment, the thread manipulation unit can have a thread braking means which comprises a thread contact section for contacting the running thread, the thread braking means being designed to brake the running thread in a defined manner by means of a braking force acting on the thread. For example, the thread braking means can be formed by the deflection means. Thread-contacting means usually have surfaces that have as little influence as possible on the running thread. For pure variable deflection of the thread path, the deflection means can be designed, according to a preferred embodiment, with such a surface coating touching the thread, so that the thread experiences essentially only a compressive force caused by the deflection in order to influence the thread tension. According to another preferred embodiment, the deflection can be provided with a friction-increasing surface coating touching the thread, which surface coating exerts a braking force on the thread in addition to the compressive force. According to an alternatively preferred embodiment, the thread braking means can be formed by a component which is assigned or can be assigned to the spinning unit and which has a surface section provided for contacting the running thread without deflecting the running thread.

The adjustment of the thread-tension-influencing force by the thread manipulation unit, e.g. the adjustment of the preferably provided deflection means and/or the preferably provided clamping means acting on the thread and/or the thread braking means preferably acting on the thread, can be carried out manually, in which case a machine operator, for example, carries out a corresponding adjustment of the thread manipulation unit for this purpose. According to a particularly preferred embodiment of the present invention, however, the thread-tension-influencing force is electrically adjustable. Electrical adjustment of the thread-tension-influencing force not only makes it more convenient to adjust the thread manipulation unit, it also enables particularly precise adjustment of the thread-tension-influencing force. For the electrical adjustment of the thread-tension-influencing force, suitable actuating motors can be used, for example, by means of which the advantageously provided deflection means, clamping means or thread braking means can be precisely adjusted in their position relative to the thread.

The thread tension can be adjusted, for example, by alignments to a suitable scale on the advantageously provided deflection means and/or clamping means and/or thread braking means.

According to an advantageous embodiment of the present invention, a sensor is provided for measuring the thread tension of the thread section that can be or is influenced by the thread manipulation unit.

The use of such a sensor, which also enables the visual display of the thread tension set by the thread manipulation unit via a suitable display unit that can be or is coupled to the sensor wirelessly or by cable, allows the thread tension to be set in a particularly precise manner. In addition, the use of such a sensor in combination with the advantageously provided electrical adjustability of the thread-tension-influencing force offers the possibility of adjusting and controlling the thread tension in an automated manner by means of suitable open-loop and closed-loop control units via a central unit without the need for manual adjustment by a machine operator. The use of such a sensor thus makes it possible to maintain a constant thread tension permanently.

In principle, the thread manipulation unit can be arranged at any point between the air-jet spinning device and the winding device at the spinning unit. According to a particularly advantageous embodiment of the present invention, however, the thread manipulation unit is arranged in the area between the air-jet spinning device and a thread take-up unit, which is adjacent to the air-jet spinning device. The thread take-up unit is, for example, a driven take-up roller pair by means of which the thread is taken up from the air-jet spinning device. Since in this area the thread tension is usually constant without the influence of the thread manipulation unit, this area is particularly advantageously suitable for bringing about a change in the thread tension by means of the thread manipulation unit. In addition, this area of the spinning unit usually has sufficient space available for the thread manipulation unit to be arranged in a straightforward manner.

The invention also solves the problem by means of an air jet spinning machine for manufacturing a thread from a supplied fibre band, comprising at least one spinning unit which is in accordance with the present invention or has been developed further, as represented above. The air jet spinning machine generally has a plurality of spinning units arranged side by side, at which threads are spun simultaneously from supplied fibre bands. The air jet spinning machine according to the present invention has the advantage that threads with inadequate thread strength values can be detected at an early stage and consequently measures can be taken immediately to eliminate any malfunctions that lead to a reduction in thread strength.

According to a particularly advantageous embodiment of the present invention, the air jet spinning machine has an evaluating unit for detecting a thread break and/or a thread break rate at the spinning units, which evaluating unit also carries out a comparison between the thread break rate and target rates that can be specified. An air jet spinning machine designed according to this further development of the present invention monitors the individual spinning units in an automated manner by means of an evaluating unit and recognises thread breaks and/or detects the thread break rate at the individual spinning units. Depending on the selectable indicators, it is thus possible to indicate this information to the operating personnel, who can then investigate the cause and, if necessary, take suitable measures to eliminate the malfunction. For example, even one thread break can be indicated by means of the evaluating unit and lead to a check by the operating personnel. Alternatively, an indication can be given depending on the thread break rate detected by the evaluating unit, e.g. an Informator of the air jet spinning machine, namely when the thread break rate deviates from an expected value in a specified manner.

According to a particularly advantageous embodiment of the present invention, the air jet spinning machine additionally has a controlling unit which serves to detect the thread tensile force by means of thread tensile-force sensors arranged at the spinning units and to adjust the thread-tension-influencing force of the thread manipulation unit. The use of a controlling unit makes it possible to set a thread-specific thread tension in an automated manner at the individual spinning units, this thread tension being a thread tension that leads to a thread break if the thread strength of the spun thread is too low. The use of a controlling unit allows automated and particularly convenient adjustment and monitoring of the spinning processes of the individual spinning units.

The invention also solves the problem by means of a method for detecting a thread strength of a thread manufactured at a spinning unit of an air jet spinning machine which falls below a target value. According to the method according to the present invention, an adjustable thread-tension-influencing force is applied to the thread by means of a thread manipulation unit, which is arranged in the area between an air-jet spinning device and a winding device and acts mechanically on the thread, a thread break and/or a thread break rate is detected and compared with a specified target rate, and the thread break and/or deviations of the thread break rate beyond a predefined limit value are indicated and/or, in particular for the initialization of measures, evaluated.

The method according to the present invention makes use of the fact that malfunctions in the spinning process of the air-jet spinning device lead to a reduction in the thread strength of the spun thread. The thread manipulation unit makes it possible to set the thread tension to a value which corresponds to the expected thread strength. If the thread strength falls below the expected thread strength due to faults in the spinning process, then the increased thread tension caused by the thread manipulation unit results in a thread break, which can be evaluated as an indication of a malfunction in the spinning process, e.g. due to contamination at the air-jet spinning device.

According to the method according to the present invention, a thread break and/or the thread break rate is detected at the individual spinning units. Depending on the process parameters to be set, even one thread break can be evaluated as an indication of malfunctions in the spinning process, so that even one thread break is indicated to the operating personnel, who then take appropriate measures. In addition or alternatively, a possible malfunction of the spinning process can be signaled to the operating personnel only when an expected thread break rate is exceeded, and the operating personnel then perform a check or eliminate any malfunction in a corresponding manner.

In particular, the spinning unit or air jet spinning machine can be a spinning unit or air jet spinning machine as described above, according to one of the preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment example of the present invention is explained below with reference to the drawings. In the drawings:

FIG. 1 shows a simplified view of an air jet spinning machine having several spinning units, according to a preferred embodiment example;

FIG. 2 shows a spinning unit of the air jet spinning machine from FIG. 1 in regular spinning operation and

FIG. 3 shows a thread manipulation unit of the spinning unit from FIG. 2 , which thread manipulation unit has clamping means.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a simplified representation of an air jet spinning machine 1 having a plurality of spinning units 2 arranged side by side, according to a preferred embodiment example. Each spinning unit 2 comprises a fibre band source 3, which can be designed, for example, as a spinning can, a drafting system 4, an air-jet spinning device 5, a take-up roller pair 6 a, 6 b, a thread clearer 7, a thread repositioning apparatus 8, a thread manipulation unit 17 as well as a cross-wound package 9 of a winding device. A service trolley 10 is movably mounted on rails 11, 12 extending along the air jet spinning machine 1. A machine end housing 13 is provided at one longitudinal end of the air jet spinning machine 1 for the arrangement of central devices required for the operation of air jet spinning machine 1.

FIG. 2 shows a spinning unit 2 according to a preferred embodiment example in regular spinning operation. A fibre band 14 supplied by a fibre band source 3 passes through a drafting system 4, in which the fibre band 14 is drafted. The drafted fibre band 14 is then fed to the air-jet spinning device 5 via a pair of output rollers 16 a, 16 b of the drafting system 4. In the air-jet spinning device 5, the outer fibres of the fibre band 14 are wound around the inner core fibres of the fibre band 14 due to the air flow generated within the air-jet spinning device 5 and thus form the wrap fibres, which are decisive for the desired strength of the thread 15. The spun thread 15 is taken up from the air-jet spinning device 5 by means of a take-up roller pair 6 a, 6 b and, after passing through the thread clearer 7 and the thread repositioning apparatus 8, is wound onto the cross-wound package 9 of the winding apparatus.

In the area between the air-jet spinning device 5 and the take-up roller pair 6 a, 6 b, the thread 15 passes through the thread manipulation unit 17, by means of which a thread-tension-influencing force is mechanically exerted on the thread 15, which thread-tension-influencing force results in an increase in the thread tension. The thread tension, which can be adjusted by means of the thread-tension-influencing force, depends on the expected thread strength, and the magnitude of the thread tension is set in such a way that, if the thread strength falls below an expected value, a thread break occurs due to the increased thread tension.

An embodiment example of a thread manipulation unit 17 for applying a thread-tension-influencing force to the thread 15 is shown in FIG. 3 . The thread manipulation unit 17 has two clamping discs 23 a, 23 b, which can set to different distances apart from one another and between which the thread 15 is passed. The clamping force acting on the thread 15 is determined by the spring stress applied by a coil compression spring 21, which spring stress in turn results from the distance between the clamping disc 23 a and a stop 22 adjustable along a shaft 20, against which clamping disc 23 a and stop 22 the opposite ends of the coil compression spring 21 rest. An adjustment of the stop 22, and thus the setting of the distance between the clamping disc 23 a and the stop 22, is carried out by means of an actuating motor 18, which is arranged on a carrier 19 and rotates the shaft 20 and is connected to an open-loop and closed-loop control unit (not shown here) of the air jet spinning machine.

According to an embodiment example not shown here, the thread manipulation unit 17 has an eyelet through which the thread 15 passes, which eyelet can be adjusted transversely to the thread running direction. The thread path is deflected by means of a displacement of the eyelet; the thread-tension-influencing force acting on the thread, in the form of a compressive force and in particular additionally in the form of a braking force, and thus the thread tension can be adjusted according to the position of the eyelet. According to a preferred embodiment example, the preferably provided additional braking force can be achieved by means of an appropriate surface coating on the surface section of the eyelet which touches or deflects the thread.

According to an embodiment example which is also not shown, a thread braking means is provided for generating such a braking force, which thread braking means comprises a thread contact section for contacting the running thread, the thread braking means being designed to brake the running thread in a defined manner by means of a braking force acting on the thread.

LIST OF REFERENCE SIGNS

-   -   1 Air jet spinning machine     -   2 Spinning unit     -   3 Fibre band source     -   4 Drafting system     -   5 Air-jet spinning device     -   6 a, 6 b Take-up roller pair     -   7 Thread clearer     -   8 Thread repositioning apparatus     -   9 Cross-wound package     -   10 Service trolley     -   11 Rail     -   12 Rail     -   13 Machine end housing     -   14 Fibre band     -   15 Thread     -   16 a, 16 b Pair of output rollers     -   17 Thread manipulation unit     -   18 Actuating motor     -   19 Carrier     -   20 Shaft     -   21 Coil compression spring     -   22 Stop     -   23 a, 23 b Clamping disc 

1. A spinning unit for an air jet spinning machine for manufacturing a thread from a supplied fibre band, comprising an air-jet spinning device for forming a thread from at least one fibre band fed via a drafting system, and a winding device for taking up the thread on a take-up package, characterised in that, in the area between the air-jet spinning device and the winding device, a thread manipulation unit is arranged, which acts mechanically on the thread and exerts an adjustable thread-tension-influencing force on the thread to variably increase the thread tension.
 2. The spinning unit according to claim 1, characterised in that the thread manipulation unit has an adjustable clamp toward the thread.
 3. The spinning unit according to claim 2, characterised in that the clamp is formed by a disc tensioner and/or gate tensioner for adjustable drawing of the thread.
 4. The spinning unit according to claim 1, characterised in that the thread manipulation unit has an adjustable deflector.
 5. The spinning unit according to claim 1, characterised in that the adjustable thread-tension-influencing force is electrically adjustable.
 6. The spinning unit according to claim 1, characterised by a sensor for measuring the thread tension of the thread section that can be or is influenced by the thread manipulation unit.
 7. The spinning unit according to claim 1, characterised in that the thread manipulation unit is arranged in the area between the air-jet spinning device and a thread take-up unit.
 8. Air jet spinning machine for manufacturing a thread from a supplied fibre band, characterised by at least one spinning unit according to claim
 1. 9. Air jet spinning machine according to claim 8, characterised by an associated evaluating unit for detecting a thread break and/or thread break rate at the spinning units and comparing the thread break rate with target rates that can be specified.
 10. Air jet spinning machine according to claim 8, characterised by an associated controlling unit for detecting the thread tensile force by thread tensile-force sensors arranged at the spinning units and for adjusting the thread-tension-influencing force of the thread manipulation unit.
 11. A method for detecting a thread strength of a thread manufactured at a spinning unit of an air jet spinning machine which falls below a target value, wherein an adjustable thread-tension-influencing force is applied to the thread by a thread manipulation unit, which is arranged in the area between an air-jet spinning device and a winding device and acts mechanically on the thread, and a thread break and/or thread break rate is detected and compared with a specified target rate, and the thread break and/or deviations of the thread break rate beyond a predefined limit value are indicated and/or evaluated.
 12. The spinning unit according to claim 1, characterized in that the adjustable thread-tension-influencing force is an adjustable braking, compressive and/or clamping force.
 13. The spinning unit according to claim 4, characterized in that the adjustable deflector is an adjustable eyelet for variably altering the thread path. 